1. Field
The invention is in the field of reversible ratchet wrenches and is concerned with structural improvements therein making for easier operation, more rugged construction, and economy of production.
2. State of the Art
Reversible ratchet wrenches are well known and widely used. They enable an applied rocking motion to be converted to rotary motion for performing work, such as the screwing of nuts onto or off of bolts, etc. Reverse operation, as from clockwise rotation to counterclockwise rotation and vice versa, is accomplished by changing the position of a pawl relative to a ratchet wheel.
In general, ratchet wrenches comprise an elongate, rigid, wrench body having, at one end, a driving member for engaging the work and, at the other end, a handle for applying the rocking motion to the driving member. A ratchet wheel is associated with the driving member at the one i.e. head end of the wrench body and a reversibly positionable, resiliently biased pawl is associated with the ratchet wheel for effecting rotation of the ratchet wheel either clockwise or counterclockwise, depending upon the position of the pawl, as rocking motion is applied to the other i.e. handle end of the wrench body.
As ordinarily constructed, the position of the pawl is changed manually by means of a change-over device extending exteriorly of the wrench body for actuation by a hand or finger of the user. In certain known constructions, the change-over device is located either at the head end of the wrench body, as in U.S. Pat. Nos. 4,277,990, 3,467,231, and 3,233,481, for direct action on the pawl, or at the handle end of the wrench body confronting the terminus of such handle end, as in U.S. Pat. Nos. 4,308,769 and 3,650,165, for action on the pawl through the intermediacy of an alongate change-over element extending longitudinally within the handle, which is hollow. In either instance, the use of two hands by the user is necessary as a practical matter to effect change-over.
U.S. Pat. No. 3,608,402 discloses a ratchet wrench having a hollow wrench body with a rotatable handle end portion operable on an elongate change-over element extending longitudinally within the wrench body, while U.S. Pat. No. 4,277,989 discloses a wrench body which is hollow intermediate the head and handle ends and contains an elongate change-over element extending longitudinally therewithin and terminating at the handle end in a change-over button exteriorly of the wrench body that can be moved longitudinally in opposite directions by a finger of the hand holding the wrench to effect change-over. To somewhat similar effect is the construction in U.S. Pat. No. 4,300,413.
While the ratchet wrenches of the last three patents are conceivably operable by a single hand of the user, they still leave room for a construction, such as that of the present invention, providing for more convenient single hand operation. Moreover, the internal operating parts of these known ratchet wrenches are quite expensive to fabricate and assemble and leave something to be desired in the way of ruggedness and durability.